343 research outputs found

    Making the most of community energies:Three perspectives on grassroots innovation

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    Grassroots innovations for sustainability are attracting increasing policy attention. Drawing upon a wide range of empirical research into community energy in the UK, and taking recent support from national government as a case study, we apply three distinct analytical perspectives: strategic niche management; niche policy advocacy; and critical niches. Whilst the first and second perspectives appear to explain policy influence in grassroots innovation adequately, each also shuts out more transformational possibilities. We therefore argue that, if grassroots innovation is to realise its full potential, then we need to also pursue a third, critical niches perspective, and open up debate about more socially transformative pathways to sustainability

    Spotting the diffusion of New Psychoactive Substances over the Internet

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    Online availability and diffusion of New Psychoactive Substances (NPS) represent an emerging threat to healthcare systems. In this work, we analyse drugs forums, online shops, and Twitter. By mining the data from these sources, it is possible to understand the dynamics of drugs diffusion and their endorsement, as well as timely detecting new substances. We propose a set of visual analytics tools to support analysts in tackling NPS spreading and provide a better insight about drugs market and analysis

    Using dynamic vascular optical spectroscopy to monitor patients with peripheral arterial disease - three exemplary cases

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    In this study, Dynamic Vascular Optical Spectroscopy (DVOS) was used to monitor the blood flow in patients affected by peripheral arterial disease (PAD) who underwent lower extremity revascularization procedures. Four different angiosomes on the foot were considered, collecting point-based measurements of the vascular dynamics during a venous cuff occlusion (@ 60 mmHg) in the lower extremity with the system shown in Fig. 1. Over 70 patients were monitored from before the intervention to up to one year later. Among them, we selected 3 exemplary cases that can highlight different hemodynamics flows in the foot of these patients. The general idea behind our research is that if a patient has a healthy vasculature, when we interrupt the venous return using a thigh cuff occlusion the saturation of the blood in the foot will be swifter than in the case of a patient in which its arterial tree is occluded and less blood can pool in the lower extremities. Please click Additional Files below to see the full abstract

    Accelerated modeling of light transport in heterogeneous tissues using superposition of virtual sources

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    We present a perturbation theory for diffusive light transport in turbid media, which allows us to model the light distribution around inhomogeneities of complex geometries. The diffusion equation for an inhomogeneous medium is transformed into an equivalent integral equation that can be solved with a fast iterative numerical algorithm. This method models three dimensional geometries considerably faster than standard methods. Furthermore, the integral formulation supports an intuitive understanding of the physical processes

    The Effect of Hot Deformation Parameters on Microstructure Evolution of the α-Phase in Ti-6Al-4V

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    The effect of high-temperature deformation and the influence of hot working parameters on microstructure evolution during isothermal hot forging of Ti-6Al-4V in the alpha phase field were investigated. A series of hot isothermal axis-symmetric compression tests were carried out at temperatures both low and high in the alpha stability field [(1153 K and 1223 K (880 °C and 950 °C), respectively], using three strain rates (0.01, 0.1 and 1.0/s) relevant to industrial press forging. The microstructures and orientation of the alpha laths were determined using optical microscopy and electron backscatter diffraction techniques. The experimental results show that there is a change in lath morphology of the secondary α phase under the influence of the deformation parameters, and that α lath thickness appears to have little influence on flow behavior

    Quantitative Modeling of Cerenkov Light Production Efficiency from Medical Radionuclides

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    There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use

    Uncovering three-dimensional gradients in fibrillar orientation in an impact-resistant biological armour

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    The complex hierarchical structure in biological and synthetic fibrous nanocomposites entails considerable difficulties in the interpretation of the crystallographic texture from diffraction data. Here, we present a novel reconstruction method to obtain the 3D distribution of fibres in such systems. An analytical expression is derived for the diffraction intensity from fibres, explaining the azimuthal intensity distribution in terms of the angles of the three dimensional fibre orientation distributions. The telson of stomatopod (mantis shrimp) serves as an example of natural biological armour whose high impact resistance property is believed to arise from the hierarchical organization of alpha chitin nanofibrils into fibres and twisted plywood (Bouligand) structures at the sub-micron and micron scale. Synchrotron microfocus scanning X-ray diffraction data on stomatopod telson were used as a test case to map the 3D fibre orientation across the entire tissue section. The method is applicable to a range of biological and biomimetic structures with graded 3D fibre texture at the sub-micron and micron length scales
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